Shaft-coupling.



H. STEINHART SHAFT COUPLING.

APPLICATION FILED JAN.31,1912.

Patented May 25, 1915.

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HERMANN STEINHABT, 0F STUTTGART, GERMANY, ASSIGNOR TO THE FIRM 0F ROBERTBOSCH, OF STUTTGABT, GERMANY.

ST-COUPHNG.

niaaeae.

Specification of Letters Patent.

Patented May 25, 1915.

To all whom it may concern:

Be it known that I, HERMANN STEINHART,

' a subject of the Emperor of Germany, re-

siding at J ohannesstrasse 56, Stuttgart, Germany, have invented certainnew and useful Improvements in Shaft-Couplings; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such aswill enable others skilled in the art to which itappertains to make and use the same.

The present invention relates to shaft couplings, and more particularlyto a spring coupling well adapted for axially abutting shafts fordriving an electric ignition machine from the internal combustion engineassociated with it.

In driving electric ignition machines of ordinary construction, thedriving force fluctuates greatly as the rotating pole pieces sweep bythe stationary magnets. In fact, the fluctuation is of such magnitudethat the coupling parts reverse their driving and driven functionsseveral times in each rotation, the normally driving part actually beingdriven by the normally driven part during some parts of each cycle.

In order to partially equalize the fluctuating character of the drivingforce, and for other well known reasons, a spring coupling hasheretofore been interposed between the driving and driven shafts, but sofar as I I am aware the coupling has been constructed in suchmanner'that the springs employed were flexed first in one direction andthen in the other direction as a result of this reversal of driving anddriven function of the parts. In consequence of continued repetition ofthis action, the spring element of such a coupling became brittle andunserviceable in practice after a comparatively short period ofoperation.

The present invention is directed to a construction avoiding the rapiddestruction of the springs due to this cause. It accomplishes thatpurpose by employing in the coupling a spring structure, preferably twomagazines of leaf springs, adapted to engage cotiperative abutments insuch manner that parts of the springs are flexed in one direction only,whether the driving and driven functions of the parts are reversed ornot and whether the direction of rotation of the engine is reversed ornot. In this way, one part of thesprings of a magazine is flexed whenthe coupling parts become angularly displaced in one direction, whilethe other part of the springs is flexed when the coupling members becomeangularly displaced in the reverse direction, as a result of which nopart of any spring is ever flexed in both directions. 7

In the accompanying drawings, illustrating the preferred embodiment ofmy invention, Figure 1 is a side elevation of the complete coupling;Fig. 2 is an end elevation of one of the coupling parts; Fig. 3 is anend elevation of the other coupling part; Fig. 4 is a side elevation ofthe coupling part of Fig. 2; Fig. 5 is a side elevation of the couplingpart of Fig. 3; and Fig. 6 is a section on line 6-6 of Fig. 1.

The coupling part shown in Figs. 2 and 4 consists of a disk or plate a,which is rigidly fastened b the wedge bolt 5 upon the end of the sha to. The disk a carries two diametrically disposed projections d, d,carrying the blocks e of fiber or hard wood. The coupling part shown inFigs. 3 and 5 consists of a disk or plate f fastened in a like manner bya wedge bolt 9 to the end of the shaft h, which, in ordinaryapplications, axially abuts the shaft 0. The disk f carries adiametrically disposed cross-piece i in which two slots is, k are madeso as to form axially extending projections: Within the slots is, twomagazines of fiat metal springs Z are fastened intermediate of theirends, by means of the bolt m, and these springs may be said to bediametrically deposed.

IVhen the two coupling parts are fixed in place, the ends of the springmagazines embrace the blocks 6 on the other coupling part, the sides ofthe blocks forming cooperative abutments for the springs. By

this arrangement, the two coupling parts may have their driving anddriven functions reversed, or the direction of rotation of the enginemay be reversed, without altering the direction of flexure of any givenpart of any of the springs Upon angular displacement of the couplingparts in one direction, the coiiperative blocks 6 flex opposite ends ofthe two magazines in one direction, while the other ends of thosesprings are not flexed at all. However, when the angular displacement ofthe coupling parts is reversed, the other opposite ends of the springmagazines are flexed, while those ends which were flexed before are nownot flexed at all. It will be obvious, therefore, that no part of anyspring is ever flexed in both directions, inasmuch as certain parts ofthe springs resist angular displacement of the coupling parts inonedirection, while other parts of the springs resist angular dis placementof the coupling parts in the other direction.

There is no abutment or similar device which resists the movement ofeither of the spring magazines in the direction of displacement of thecoupling parts, and therefore it may be said that the springs l are freeto flex in the direction of the displacement.

Having thus described my invention, what I claim is:

1. A flexible coupling for abutting shafts comprising a coupling partfastened to each shaft, a diametrically-disposed flat spring of metalfastened intermediate of its ends to one coupling part, and cooperativeengaging means lying entirely on the same side of the spring and onopposite sides of the axis of rotation so as to have driving engagementwith a single end of the spring at a time, the driving engagementoccurring at one end of the spring upon angular displace ment of thecoupling parts in one direction and occurring at the other end of thespring upon angular displacement of the coupling parts in the otherdirection, and the spring being free to flex in the direction of thedisplacement of the coupling parts; substantially as described.

2. A flexible coupling for abutting shafts comprising a coupling partfastened to each shaft, two diametrically-disposed springs of metalfastened to one coupling part, and a rigid abutment on the othercoupling part extending in an axial direction between the ends of thetwo springs so as to have driving engagement with a single one of thesprings at a time, the driving engagement occurring at one spring duringangular displacement of the coupling parts in one direction andoccurring at the other spring dur- I ing angular displacement of thecoupling parts in the other direction, and the springs being free toflex in the direction of the disone end of each spring upon angulardisplacement of the coupling parts in one direction and with the otherend of each spring upon angular displacement of the coupling parts inthe reverse direction so as to avoid reverse flexure in both ends of thesprings upon reversal of the driving and driven functions of thecoupling parts, the arrangement being such that the ends of the springsare free to flex in the direction of the displacement of the couplingparts; substantially as described.

4. A flexible coupling for abutting shafts comprising a coupling partfastened to each shaft, axially extending projections on one of thecoupling parts, two diametrically disposed magazines of flat metalsprings fastened intermediate of their ends to said projections, anddiametrically disposed abutments of rigid material on the other couplingpart arranged to project between said magazines to effect drivingengagement with one end of each magazine upon angular displacement ofthe coupling parts in one direction and with the other end of eachmagazine upon angular displacement of the coupling parts in the reversedirection so as to i avoid reverse flexure in both ends of the 'HERMANNSTEINHART.

Witnesses MAx ANsoHii'rz, PAUL WOLFART.

